Oculus co-founder Brendan Iribe

Social-networking behemoth Facebook has been going through a rough stretch when it comes to keeping key executives -- specifically, co-founders of companies that Facebook has acquired -- in the fold. The latest to leave: Brendan Iribe, co-founder of virtual reality specialist Oculus, which Facebook acquired four years ago for nearly $2 billion. In a Facebook post on Monday, Oct. 22, Iribe said he'll be taking his time off to "recharge, reflect and be creative."

Instagram co-founder Kevin Systrom

Last month, it was the co-founders of Facebook-owned Instagram who stepped down. "We're planning on taking some time off to explore our curiosity and creativity again," Kevin Systrom wrote in September. "Building new things requires that we step back, understand what inspires us and match that with what the world needs; that's what we plan to do."

Instagram co-founder Mike Krieger

Oculus co-founder Palmer Luckey

Iribe wasn't the first co-founder of Oculus to leave Facebook. That honor went to Palmer Luckey, who departed in March 2017. Facebook saluted him this way at the time: "Palmer's legacy extends far beyond Oculus. His inventive spirit helped kickstart the modern VR revolution and helped build an industry."